1. Field of the Invention
The present invention generally relates to a unit used in combination with a conventional microwave oven, without modification of the oven, in the form of an adjustable controller to control the amount of radiation reaching the food being heated or cooked.
2. Description of the Prior Art
Microwave ovens have come into widespread use in the preparation of various foods. Microwave ovens utilize microwave energy generated by a magnetron which is emitted in a manner to strike a slowly revolving fan or "mode mixer" which reflects the microwave energy and causes it to bounce off all of the surfaces of the oven so that it enters the food from all sides to cook it evenly throughout. While microwave ovens have been utilized extensively in homes, they have also been promoted heavily for commercial or institutional feeding and they have come into widespread use in hospitals, restaurants, and the like. Even though microwave ovens have received substantial acceptance, there is still a substantial lack of knowledge regarding the characteristics of the microwave radiation inside an oven. It is known that reflected radiation is uneven, constantly varies and is quite unpredictable. Another factor involved is the different and sometimes unexpected behavior of various foods when exposed to radiation. In some instances, food will heat erratically and with unusual time parameters or sometimes not at all. Some foods will burn but not brown while others become extremely hot at the center and remain cool at the edges, while in others just the reverse occurs. Increases in mass are not necessarily or always proportional to extended cooking times and some foods tend to disintegrate or literally explode when certain conditions occur.
Prior Pat. No. 3,271,169, issued Sept. 6, 1966, to Baker, et al., discloses some of the problems which are inherent in preparing food in a microwave oven and apparently discloses one of the first efforts to solve some of the problems relating to microwave oven cooking. U.S. Pat. No. 3,302,632, issued Feb. 7, 1967, to Richtner, discloses a utensil for use in microwave heating of different foods and generally is in the form of a prepackaged meal. U.S. Pat. No. 3,547,661, issued Dec. 15, 1970, to Stevenson, discloses a container for use in a microwave oven which is constructed in a manner to heat different foods in the container to different temperature levels which requires the provision of a variety of container sizes and types which introduces inherent problems of matching the container availability with utility requirements. U.S. Pat. No. 3,615,713, issued Oct. 26, 1971, to Stevenson, discloses another special container for heating or cooking different foods to a different degree and would also require a large supply of various containers to match the requirements of every type of food and various serving sizes, and the like.
While attempts have been made to heat or cook various foods placed in a microwave oven to different desired temperature levels or conditions, such attempts generally have related to the provision of special containers for the diverse foods, which requires a supply of such containers, thus necessarily increasing the cost and time involved since the food, after it has been cooked or heated in the special containers then must be placed in a serving dish before it is delivered to the ultimate consumer.